A scientist investigated the effects of morning temperatures on flower width. Which most likely could have been a source of error in his investigation? A. The distance calipers were recalibrated before each data collection session.
B. The control group flowers were a day older than the experimental group flowers.
C. The measurement units were not converted during the data analysis phase.
D. The flower width data were collected at about the same time every day.

answer; i believe that the correct answer is (a) potassium(k)

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.

a corroding iron, if that's one of your choices

it’s previous models   because when i picked that son of a gun’s answer it was wrong look for previous models because they might make it a different letter